Enameling and annealing furnace



P. DUPONT.

ENAMELING AND AN NEAL|NG FURNACE. APPLICATION FILED MAR. 14, 191B.

. I Patented Mar.'30,

UNITED STATES PATENT OFFICE.

PAU DUPONT, OF PARIS, FRANCE.

ENAMELING AND ANNEALING FURNACE.

Application filed March 14, 1918.

To all whom it may concern:

Be it known that 1, PAUL DUPONT, a citizen of the Republic of France, residing at Paris, France, have invented new and useful Improvements in Enameling and Annealing Furnaces; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to improvements in enameling and annealing furnaces and is shown in the annexed drawings as applied to the enameling of a bath, but it is obvious that it may be made of any suitable shape corresponding to that of the object or article to be enameled.

Figure 1 is a transverse section of my improved furnace and Fig. 2 is a part of a transverse section relating to'a modification of the furnace shown in Fig. 1.

The furnace consists of an outer wall or sheath C and an inner wall A of highly porous refractory material of suitable thickp ness, and having prefeTably the shape of a bath such as B and of suitable size to allow for a proper space. a being formed between ,the wall and the bath B; after the latter has been introduced into the furnace.

This refractory inner wall is covered outside with a metal sheath 0 having extensions c with slightly turned up edges serving to support the edge 2) of the bath. By suitable means such, for example, as the collars rl formed in the wall A, a very small space a is maintained between the wall and its sheath, so as to allow a free circulation of the gaseous mixture for heating the furnace, as hereinafter more fully explained. At different parts of the sheath, provided with correspondin apertures, are attached short tubes D for t e introduction of a mixture of combustible gas and air or oxygen under pressure. The combustible gas, the proportions'of the mixture and its pressure may be varied according to the temperature which it is desired to obtain. The combustible gas can, for example, be the town lighting gas, acetylene, hydrogen, or any other suitable gas. Wire gauze partitions f are arranged perpendicularly in the inlet pipes D for the mixture so as to prevent the'ignition of the gas in the said pipes. On the sheath are also arranged small ignltion burners E, extending to the inner Specification of Letters Patent.

Patented Mar. 30, 1920.

Serial No. 222,449.

face of the wall A and connected independently of the combustible mixture directly to the source of combustible gas, as well as a discharge passage F for the burnt gases communicating with the interior of the furnace by means of openings G in the wall A.

The arrangement ust described constitutes the furnace proper. It can advantageously be mounted upon a double support in such a manner as to be suitably inclined longitudinally and transversely for purpose of facilitating the powdering of inner face of the bath B which is introduced therein.

This furnace is completed by a fiat cover of analogous construction, that is to say, provided with a lining A of very porous refractory material contained in a metal sheath C with a small intermediate space 6 and short tubes D for the introduction of combustible mixture, ignition burners E and openings and discharge passage G, F. The wall A of very porous refractory material is, however, replaced at the angles by angle ieces K of non porous refractory material for protecting the edge 1 of the bath from too fierce a fire. Moreover, a mica-covered peep-hole, (not shown) is provided at a suitable point of the surface of the cover for ascertaining the degree of heat in the bath under treatment.

For cast iron articles an auxiliary stove heated by the burnt gases issuing from the furnace through the passages F before their escape into the air may be used as usual, in order to raise the bath to a given temperature before it is placed in the furnace.

The different passages opening into the apparatus are provided with regulating devices such as dampers, valves, etc., and a flexible portion for allowing the displacement of the furnace proper and of its cover.

The discharge passages F for the burnt gases may be preferably, provided for a certain portion of their length with a double casing through which an air is blown under pressure in order to be heated before being mixed with the combustible gas, so as to increase the temperature of combustion of the mixture in the furnace.

The furnace is employed in the following manner:

After having previously heated the bath in the auxiliary stove aforesaid, it is placed in the furnace proper, on which the cover is then placed as shown in Fig. 1, then the distributed first, in the I ward throughout the mass of the said porous I neartogether to combustible mixture is admitted which, by reason of the resistance offered to its passage by the refractory material A, becomes space e and afterrefractory material. Immediately after it has passed through the latter it is ignited by the burners E, which are always alight, in order to avoid any risk of explosion.- The wall A is thus rapidly brought to incandescence, its thickness being calculated according to the nature-of the gas employed, so as to obtain this result.

When it has been found by the peep-hole in the cover, that the bath has reached the roper degree of temperature, the cover is ifted by means of a Windlass and chains for example; But the furnace proper, always heated, is suflicient for continuing to raise the temperature of the bath .B while the operator is proceeding to the powdering which can thus be effected in a single operation.

In some cases the thickness of the refractory material of the wall A can be lessened sons to leave between it and the outer metal sheath 0 a larger space 6 Fig. 2 into which can open a series of burners L uniformly distributed over the whole surface of the sheath in order to bring, the said refractory material to incandescence. case the refractor material used can be porous or not an reinforced by a metal plate M which will increase its resistance. Ignition burners E'similar to those before mentioned would serve always for lighting the burners which would be then sufliciently revent explosions.

It is obvious t at the described furnace for enameling baths is applicable, with suitable modifications of the shape, for enameling and,'in a more general manner, for the heating of any metal. articles. I Y

I claim as my invention:

1. In a furnace, the combination of a bath,

a source of combustible material, means between the bath and the source of combustible In thisv material to effect adistribution of the un ignited combustible material around the bath and means between the first-named means rial.

a source of combustible material, a permeable layer between the bath and the source.

and the bath to ignite the distributed mate- 2. In a furnace, the combination of a bath,

shape suitable for the objects to be treated therein, consisting of an inner wall of porous refractory material, an outer wall or sheath and an intermediate space between thetwo for the free passage of gas, .said' sheath being provided with short tubes for the mikture of'combustible gas and air under pressure, while ignition burners '-protrude through said inner wall, and a conduit for burnt gases communicates with the inside of thefurnace by suitable openings, said fur "nace being surmounted by a lid or cover of similar construction to that of the chamber provided withf angles pieces of nonporous material. 1

4. In furnaces for enameling and annealing, the combination of a cham I suitable for the objects to be treated therein, I

er of'a shape consisting of an inner wall of-porous refractory material, an and a small intermediate space between the two maintained'by a number of collars, said sheath having extensions with turned up edges and short tubesfprovided with wire gauzed'partitions' to prevent ignition as and for the purpose set forth. H

outer wall or sheath In witness whereof, I have hereunto signed I my name in'the presence o'ftwo subscribing witnesses.

PAUL DUPONT. Witnesses:

CHAs. P. PiinssLY, HENRI CARTIER. 

